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Function of Transcriptional mediator

转录介质的功能

基本信息

批准号：
06454673
负责人：
HIROSE Susumu
金额：
$ 4.22万
依托单位：
National Institute of Genetics
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06454673/
关键词：
Trnascription Transcription factor Drosophila

项目摘要

Transcriptional activation of the Drosophila fushi tarazu gene by FTZ-F1 requires two additional factors MBF1 and MBF2. We have purified these mediators from posterior silk glands of the silkworm and cloned cDNA's coding for the factors. MBF1 appears to be a basic protein consisting of 146-amino acid residues and conserved across species from yeast to human. It interacts with FTZ-F1 and increases the FTZ-F1 binding to DNA.This interaction requires the C-terminal half of the FTZ-F1 box within the DNA-binding domain of FTZ-F1. MBF1 also makes a direct contact with TATA element-binding protein TBP.MBF2 is a basic protein consisting of 92-amino acid residues. Native MBF2 bears polysacharides through N-glycoside bonds. MBF2 forms a heterodimer with MBF1 and also binds to beta-subunit of TFIIA.When MBF2 alone was added to transcription mixtures, it activated transcription from various promoters. In contrast, it selectively activated transcriptoin from ftz promoter in the presence of MBF1 and FTZ-F1. Both non-selective and selective activation requires TFIIA.From these results, we have proposed the following model for transcriptional activation by FTZ-F1. MBF1 is a bridging factor that connets between FTZ-F1 and TBP and recruits the positive cofactor MBF2 to a promoter carrying the FTZ-F1-binding site. MBF2 activates transcription in a FTZ-F1-binding site dependent manner through its interaction with the beta-subunit of TFIIA.

FTZ-F1对果蝇fushi tarazu基因的转录激活需要两个额外的因子MBF 1和MBF 2。我们从家蚕后部丝腺中纯化了这些介质，并克隆了编码这些因子的cDNA。MBF 1是一种由146个氨基酸残基组成的碱性蛋白质，从酵母到人类都是保守的。它与FTZ-F1相互作用并增加FTZ-F1与DNA的结合。这种相互作用需要FTZ-F1的DNA结合结构域内的FTZ-F1盒的C末端一半。MBF 1也与TATA元件结合蛋白TBP.MBF2是由92个氨基酸残基组成的碱性蛋白。天然MBF 2通过N-糖苷键携带多糖。MBF 2与MBF 1形成异源二聚体，并与TFIIA的β亚基结合，当MBF 2单独加入到转录混合物中时，它激活来自各种启动子的转录。相反，在MBF 1和FTZ-F1的存在下，它选择性地激活来自ftz启动子的转录肽。非选择性和选择性激活都需要TFIIA。根据这些结果，我们提出了以下FTZ-F1转录激活模型。MBF 1是连接FTZ-F1和TBP之间的桥接因子，并将正辅因子MBF 2募集到携带FTZ-F1结合位点的启动子。MBF 2通过其与TFIIA的β亚基的相互作用以FTZ-F1结合位点依赖性方式激活转录。